This disclosure relates to lighting or lamp assemblies and more particularly to a compact fluorescent lamp (CFL) or lamp assembly. It finds particular application when used in an A-line lamp profile, and particularly one where the discharge tube of the compact fluorescent light source has a spiral or double helix conformation. Selected aspects, however, may find application with other compact fluorescent light sources or lamp assemblies.
In current compact fluorescent lamp arrangements, electrodes provided in the lamp ends of an elongated discharge path protrude into a ballast compartment. This structural arrangement locates the electrodes adjacent the ballast so that lead wires extend only a short distance between the ballast and the electrodes. In compact fluorescent lamps of this type, the compact fluorescent light source is oftentimes a spiral, coiled, or helical discharge tube arrangement. An enclosing light transmissive, glass envelope or outer bulb has a generally spherical portion dimensioned to receive the CFL discharge tube therein. The outer envelope typically includes an elongated necked portion or generally cylindrical portion extending between the generally spherical portion and a lamp base. The ballast is located in the necked down region, for example, and is oftentimes a printed circuit board (PCB) that receives additional electronic components that are mechanically and electrically connected on the PCB for connection with the electrodes of the discharge tube of the CFL. An additional set of lead wires extend from the ballast/PCB and make contact with electrical contacts in the base of the lamp. For example, one type of common arrangement for the base is what is commonly referred to as an Edison base that includes a threaded, electrically conductive shell that defines a first contact and that is separated from a ring or second contact located at a terminal end of the base. The ring contact and the threaded shell are typically separated by an insulating material in a manner well known in the art.
Prior lamp arrangements of this type sometimes employ a dividing wall that has first and second openings to receive the first and second discharge tube ends and likewise the electrodes of the discharge tube. The dividing wall is usually located at the juncture between the substantially spherical portion of the outer envelope and that region where the glass envelope merges into the necked down region. The dividing wall provides some additional thermal protection to a ballast compartment defined below the dividing wall from the remainder of the coiled discharge tube received in the generally spherical portion of the envelope. In this manner, an A-line lamp configuration is provided that employs an efficient low energy lamp such as a compact fluorescent light source.
Even with these proposed solutions, known CFL arrangements impose substantial thermal stress on the electronic components of the ballast arrangement. This thermal stress results in a shorter lamp life or requires use of more expensive electrical components that are able to withstand the thermal impacts. Consequently, a need exists for reducing the thermal stress of the electrical components of a ballast circuit or PCB.